It is an object of the present invention to provide an adjustable guide vane ring for a turbomachine that will make it possible to reduce amounts of circulating air leakage. It is also an alternate or additional object of the present invention to provide a compact inner ring for a guide vane ring of this kind. It is also an alternate or additional object of the present invention to provide a turbomachine that has a high compressor efficiency.
An inventive adjustable guide vane ring of a turbomachine has a plurality of guide vanes forming a guide vane row and an inner ring for stabilizing the guide vane row. The guide vanes each have an adjusting pin, which is disposed radially outwardly relative to a longitudinal axis of the ring and is provided for cooperating with an adjusting device. The inner ring is split radially and mounted axially together and, viewed in the direction of a primary flow, has a front ring segment and a rear ring segment. In accordance with the present invention, the inner ring bears a brush seal for sealing a gap between the inner ring and an opposite rotor portion.
Providing a brush seal in accordance with the present invention reduces the amount of circulating air leakage since the brush seal is not able to rub gaps into the opposite rotor portion, nor is the opposite rotor portion able to rub gaps into the brush seal. The brushes, respectively the brush portion of the brush seal, deform(s) elastically in response to a relative movement of the rotor toward the stator, so that no plastic gaps remain even after a substantial relative movement. In addition, the number of required components is reduced since the need is eliminated for rotor-side sealing webs, as well as for the antiwear coating thereof, for example. Moreover, weight is economized due to the reduced number of components required for the brush seal. The brush seal is preferably radially oriented. However, it may also be axially or diagonally oriented relative to the longitudinal axis of the ring. The opposite rotor portion is to be oriented as a function of the orientation of the brush seal, respectively the brush portion thereof.
In one exemplary embodiment, the brush seal is configured with the holding portion thereof in a receiving space between the ring segments that is bounded by the two ring segments. Thus, when the ring segments are installed, the brush seal is simultaneously fixed in position. Functions are integrated, simplifying installation and thereby leading to a cost saving.
In one preferred exemplary embodiment, the brush seal is passed by the brush portion thereof through a leadthrough region out of the receiving space that is wider than the brush portion in the leadthrough region. This enhances the flexibility of the brush seal since the brush portion has a considerable free length. Thus, it is able to deform elastically, starting with the holding portion.
The brush portion preferably rests against the front ring segment. This measure makes possible an exact neutral position, as well as an operating position, as well as a visual control of the installation position.
Installation of the brush seal may be simplified when it is composed of ring element parts. It is preferably composed of two ring element halves, respectively ring element parts, which each span an angle of 180°, respectively whose parting plane is identical to a circumferential parting plane of the inner ring. This makes it convenient to install the brush seal, together with the inner ring, in housing halves of a turbomachine. This type of construction may also analogously feature a segmented design. For example, the brush seal may be composed of three, four or more ring element parts or be a slotted spring ring.
The ring segments of the inner ring may be connected by bolted or riveted connections, for example. Both connection types permit a load-bearing connection of the ring segments and thus also a load-bearing positioning of the brush seal. The bolted or riveted connection secures the brush seal radially by a form-locking engagement and, circumferentially, by a frictional engagement. The ring segments are preferably riveted to one another since less outlay is required for a riveted connection than for a bolted connection. Nevertheless, in addition to a frictional connection and/or a form-locking connection, a material-to-material bond or a frictional engagement may also be suitable types of connection. For example, in machine areas having a reduced temperature, such as in the compressor areas, it is fundamentally conceivable to bond the ring segments to one another.
In one exemplary embodiment, the ring segments are manufactured differently. For example, the front ring segment is a forged part, while the rear ring segment is a reshaped sheet-metal section. Likewise conceivable is a combination of a forged part with a sheet-metal section. The different manufacturing advantageously permits a weight optimization since the ring segments may be optimized in accordance with the thermal, mechanical and chemical stresses thereof.
A vane plate is preferably used to position the guide vanes in the inner ring. Thus, radially inwardly, the guide vanes are pivot pin-free. Omitting the pivot pin and thus also the bearing bushings and, instead, directly supporting the guide vanes via the vane plates thereof in the inner ring, make it possible for the inner ring to be formed at a reduced height in comparison to the known inner rings, making possible a use in small compressors. Because the number of parts is reduced, it is also possible to reduce losses due to leakage, decrease the weight and the costs of the guide vane ring. By omitting the pivot pins and the bearing bushings, a radial installation space is achieved that permits an optimal orientation and positioning of the brush seal. In and of itself, the enlarged installation space makes it possible to select the brush seal that will have the optimal properties for the particular turbomachine. The connecting elements, such as screws and rivets, may thereby be configured to be easily accessible and, therefore, permit an easy assembly.
A preferred inner ring for a guide vane ring according to the present invention has a brush seal for sealing a gap between the inner ring and an opposite rotor portion. An inner ring of this kind is distinguished by a compact and weight-saving type of construction. The inner ring according to the present invention fulfills two important functions. On the one hand, it supports the guide vanes radially inwardly. On the other hand, it forms a receiving space for the brush seal and thus for the entire inner air seal1, since the need for rotor-side sealing webs is eliminated. Thus, the inner air seal is completely integrated in the inner ring. In contrast to conventional inner rings having a honeycomb seal that is able to be slid on circumferentially, the function of the inner air seal is integrated in the inner ring.
A preferred turbomachine has at least one guide vane ring that is adjustable in accordance with the present invention. It has a brush seal for sealing a gap between the inner ring and an opposite rotor portion. This makes a high compressor efficiency attainable since amounts of circulating air leakage in the area of the guide vane ring are reduced.